Load transfer unit for paving joint structures



May 18, 1943 R. G. WILLIAMS F-i'led Sept. 50, 1939 LOAD-4 TRANSFER UNITFOR P AVING JOINT STRUCTURES INVENTOR l RULLAND WlLLlAMa ATTORNEYPatented May 18, 1943 LOAD TRANSFER UNIT FORl PAVING JOINT STRUCTURESRolland G. Williams, Fort Myers, Fla., assignor to Malleable IronFittings Company, Branford, Conn., a corporation of ConnecticutApplication September 30, 1939, Serial No. 297,246

1 Claim.

The present invention relates to improvements in load transfer unit forpaving j oint structure, or other structures of similar nature, and hasfor an object to provide a load transfer unit which will eifectuallymaintain the adjacent ends of pavement or other sections, which areseparated by an expansion and contraction filler strip of cork or thelike, in accurately aligned level relation with each other over the fullwidth of the structure, and which will allow for the free expansion andcontraction of the sections when subjected to extreme temperaturechanges. According to the invention a series of spaced load transferunits are adapted to be arranged across the width of the ller stripbetween adjacent sections, the load transfer units adapted to haveexpanding and contracting movement in parallel relation to the length ofthe pavement or other structure, and it is an object of the invention toprovide a load transfer unit which may be assembled with similar loadtransfer units in such manner as to positively insure their parallelrelation to each other. and thus prevent any possibilityof breakage ofthe load transfer units or cracking of the pavement or other structuredue to the locking or binding action of a joint which may not beinparallel relation. A further object is to provide a load transfer unitwhich may be assembled with the filler strip and with supporting bars inaccurately aligned relation, and which will enable such assembly to beperformed upon the pavement or other construction job by relativelyunskilled workers, the assembly being such that accuracy of alignmentwill be assured without the necessity for any skill or judgment on thepart of the person assembling the parts.

A further object is to provide a joint which when assembled in relationto the ller strip may be placed upon the subgrade of the roadpreparatory to pouring the concrete pavement surface,

and which in such relation will be rigidly supported againstdisplacement through impact therewith, such as may occur by a workmanstepping upon the load transfer unit or dropping or placing objectsthereon. Another object is to provide a load transfer unit which will beeffectually sealed against the entrance of moisture and will besubstantially free from the effects of corrosion.

A further object is to provide a load transfer unit consisting of twomain parts, one of these parts being in the form of a socket member andthe other in the form of a plunger member, thus providing for simplicityof construction and assembly, and increased strength. A still furtherobject is to provide a joint support in which the main parts may beconveniently and economically produced from metal such as malleableiron, having relatively great strength against breakage and cracking andbeing highly resistant to corrosion, pitting and rust.

With the above and other objects in view, an embodiment of the inventionis shown in the accompanying drawing, and this embodiment will behereinafter more fully described with reference thereto, and theinvention will be finally pointed out in the claim.

In the drawing:

Fig. 1 is a perspective view showing the several parts of the loadtransfer unit in separated relation, and also showing in separatedrelation the supporting channel bars and the filler strip to be clampedbetween the members of the load transfer unit.

, Fig. 2 is a plan view of the load transfer unit in assembled relationwith theV channel bars and the liller strip.

Fig. 3 is a longitudinal vertical sectional view of the adjacent ends ofpavement sections showing the load transfer unit and the iller strip inoperative relation therein, the load transfer unit being shown partiallyin side elevation and partially in longitudinal section.

Fig. 4 is a transverse vertical sectional view taken along the line 4-4of Fig. 2.

Fig. 5 is a plan view', on a reduced scale, of the adjacent ends of twopavement sections.

Fig. 6 is a perspective View showing a portion of one of the channelbars, and also showing in separated relation a load transfer unitattaching lug member.

Similar reference characters indicate corresponding parts throughout theseveral vfigures of the drawing.

Referring to the drawing, the load transfer unit, according to theexemplary embodiment of the invention illustrated therein, comprises twomain members, one being a plunger member and the other a socket memberto receive the plunger member. The plunger member consists of ahorizontally disposed bar I0 provided with `a downwardly extendingmounting portion II having a bolt receiving hole I2 adjacent its lowerend, the bar I0 being provided at its inner end with an annular clampingflange I3 and a cylindrical plunger extension III. The `iiange I3 isprovided at its upper side with a pair of upwardly projecting spacedlugs I5 lfor the purpose of receiving between them a positioning bolt aswill hereinafter more fully appear. The plunger member is preferably inthe form of a casting of malleable iron, the plunger portion I4 beingformed integral with the bar I and being then machined to give it asmooth cylindrical surface. The bar I0 is preferably iiat at its upperside and curved at its lower side, as shown clearly in Fig. 4, thiscrosssectional shape being such that the concrete forming the pavementstructure will flow around it preventing the formation of voids beneaththe bar.

The socket member comprises a horizontally disposed supporting bar I6provided with a downwardly extending mounting portion I'I providedadjacent its lower end with a bolt receiving hole I8, the arm I6 havingformed upon its inner end a cylindrical socket portion I9 which ismachine-bored, as at 20, to receive the plunger I4 with a relativelysnug slide fit. The socket portion I9 is provided at its inner end witha clamping ange 2I, provided at its upper side with a pair of spacedlugs 22 for the purpose of receiving a positioning bolt, as willpresently more fully appear.

The supporting portions I I and I1 of the plunger and socket members aresecured to identical spaced parallel foot bars 23-23 of channelcross-section having their flanges projecting downwardly. These bars23-23 extend substantially the full width of the pavement, preferablyterminating a short distance from the side edges, as shown in Fig. 5,and each provided with a plurality of slots 24 correspondingly andexactly spaced. In each slot there is secured an upwardly projecting lugmember 25 having an integral rectangular base 2S, and a bolt receivinghole 21, each lug being assembled with the bar by forcing it upwardlythrough the slot 24 with such pressure as to swedge the lug in the slot,the bases 26 being forced tightly into the channel of the bar. Thesupporting portions II and I1 are secured to the lugs 25 of the pair ofbars 23-23 by means of bolts 28 and nuts 29, so that the pair of barshas Va series of load transfer units mounted thereon, the accurateposition of the slots 24 and lugs 25 insuring the exact parallelrelation of the units to each other. It will be understood that the loadtransfer units may be spaced any desirable distance apart, and that anydesired number may be employed, depending upon the width of thepavement.

The filler strip 3 I, which is adapted to permit of expansion andcontraction of the adjacent sections of pavement, extends the full widthof the pavement and corresponds in width to the thickness of the roadsurfacing material. This strip is provided substantially along itscenter line with a series of apertures 32 spaced in correspondence withthe spacings of the slots 24 and lug 25 along the channel foot bars23-23 and being of a diameter to receive the plungers I4 of the jointsupports. The filler strip 3I is preferably formed of compressed corkcomposition or other suitable material, the use of such material beingstandard practice in paving construction.

In spaced relation above each of the holes 32 there is provided a hole33 for receiving a clamping bolt 34 engaged with the lugs I5 and 22 andsecured by a nut 35 to clamp the two members of the load transfer unitwith respect to the ller strip 3 I. This bolt 34 is for the purpose ofclamping the fianges I3 and 2I and insuring proper vertical alignment ofthe two members of the load transfer unit. It also enables the personassembling the load transfer units with the filler strip and channelfoot bars 23--23 to accurately position the several load transfer unitsso that they will be in true parallel relation prior to placing the sameupon the road subgrade. The bars 23-23 may be secured in place by meansof the bolts and nuts, either before or after the assembly of the loadtransfer units with the filler strip, and this operation may either becarried out upon the paving construction job or the load transfermembers may be secured to the bars before delivery to the paving job. Itwill be understood that any suitable means may be employed to secure theload transfer members to the channel foot bars, as for instance rivetsor eyelets, and that the workmen on the paving job may be provided withthe necessary tools to secure them.

The filler strip with the load transfer units mounted thereon is laid inits proper position upon the subgrade 36 of the road bed, the downwardlyprojecting flanges of the channel foot bars being preferably embedded inthe subgrade, as shown in Fig. 3. Thereupon the'concrete forming theadjacent pavement sections 37 and 38 is poured thus embedding the twomembers of the load transfer units, which thereupon become iixedly setin the respective sections. The several load transfer units disposedalong the 'width of the pavement provide an effective joint connectingthe two sections of the pavement and supporting them against verticalor'sidewise displacement, so that one section cannot drop or lift up orshift sidewise with respect to the other. The joint between the pavementsections will therefore effectually maintain level relation irrespectiveof uneven loads upon the two sections, or sinkage of the road be-d atone side of the joint to a greater extent than the other.

Upon expansion and contraction of the pavement sections when subjectedto extreme changes of temperature the plunger of the load transfer unitforming a rigidly set part of one pavement section, and due to themanner in which the sevforming a rigidly set part of the other pavementsection, and due to the manner in which the several load transfer unitsalong the Width of the pavement are accurately positioned the parallelrelation of the plungers and sockets of each unit will be maintained, sothat there will be no possibility of binding or locking. The parts beingpreferably formed of malleable iron there will be little tendency tocorrode or rust, and also the machined surfaces of the plunger andsocket Will be substantially free frorn pitting, as distinguished fromcold rolled steel, or other such meti. al, heretofore employed in jointsupports. The

plunger may if desired be coated With a suitable lubricant, both for thepurpose of making it slide easily in the socket and to resist corrosion.

The bolt 34 and nut 35 are such that upon contraction of the roadsections and spreading oi 'the joint the threads of the bolt and nutwill strip or the bolt will break. This bolt and nut has no function inthe joint when it is embedded in the concrete, its function being simplyto primarily position the lc-ad transfer unit with respect to the fillerstrip.

As shown in Fig. 5 the several load transfer units may be alternatelydisposed in opposite directions, that is, the plunger members of thealternate units may project in one direction and those of the otherunits in the other direction. This is an alternative arrangementhowever, and the units may if desired, all extend in the same direction.

While the invention has been described particularly with reference topavement construction, it may be adapted, without materially changingthe fundamental features outlined herein, to construction of retainingwalls, dams, reservoirs and other concrete structures requiringexpansion and contraction joints.

I have illustrated and described a preferred and satisfactory embodimentof the invention, but it will be understood that changes may be madetherein, within the spirit and scope thereof, as defined in the appendedclaim.

Having thus described any invention, what I claim and desire to secureby Letters Patent is:

In a load transfer unit for the joint between adjacent sections ofsectional construction in which a ller strip is disposed verticallybetween the ends of the sections, a one-piece socket member comprisinga' horizontal socket portion adapted to be embedded in the end of onesection of the construction having a cylindrical axially extendingsocket open at one end and closed at the other end and having aperipheral flange at its open end adapted to be embedded in said sectionwith its outer surface substantially in the vertical plane of the end ofsaid section, and a downwardly extending supporting and anchoring legintegral with the closed end of said socket part, and a one-pieceplunger member comprising a supporting part adapted to be embedded inthe end of an adjacent section of the construction and having aperipheral flange adapted to be embedded in said last mentioned sectionwith its outer surface substantially in the vertical plane of the end ofsaid section, a downwardly extending supporting and anchoring legintegral with said supporting part, and a horizontal cylindrical plungerpart integral with and projecting from said anged supporting part, saidplunger part having freely sldable closely fitting engagement with saidcylindrical socket of said socket part, whereby relative movementbetween said socket and plunger members occurs entirely within onesection of the concrete.

ROLLAND G. WILLIAMS.

CERTIFICATE OF CORRECTION patent No. 2,519,715.. May i8, 19h5- ROLLANDG. WILLIAMS.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,second colurnn, line h2, for "section, and due to the manner inwhich theseV- read --sectonwillmove back and forth in thev socket; and that thesaid Letters Patent should be read with this correction therein that thesame may conform to the record of the case in the Patent Office.

signed and sealed this 15th day of July, A. D. 19M.

Henry Van Arsdale,

(Seal) Acting Commissioner of Patents.

